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Article
Publication date: 1 February 1992

W.P. Dobbins

In SMT manufacturing, automation is the key to achieving the highest throughput at the lowest cost. Complex devices of various shapes and sizes often require final electrical…

Abstract

In SMT manufacturing, automation is the key to achieving the highest throughput at the lowest cost. Complex devices of various shapes and sizes often require final electrical adjustments under operating conditions to ensure conformance to electrical specifications. This paper describes the process of laser trimming completed SMT devices and the advantages it has over conventional trimming methods. The material presented is based on laser trimming systems currently used in SMT production applications that will also be described.

Details

Soldering & Surface Mount Technology, vol. 4 no. 2
Type: Research Article
ISSN: 0954-0911

Article
Publication date: 20 June 2016

Eirin Bar, John Reidar Mathiassen, Aleksander Eilertsen, Terje Mugaas, Ekrem Misimi, Ådne Solhaug Linnerud, Cecilie Salomonsen and Harry Westavik

Practically all salmon fillets produced in Norway are trimmed clean of unwanted fat, bone remnants and other defects according to customer requirements. In today’s modern…

Abstract

Purpose

Practically all salmon fillets produced in Norway are trimmed clean of unwanted fat, bone remnants and other defects according to customer requirements. In today’s modern salmon-processing plants, the trimming operation is performed by a combination of automated trimming machines and manual post-trimming. Manual post-trimming is necessary due to the inability of current trimming machines to obtain satisfactory trimming. The purpose of this paper is to describe the work done so far toward a robotic post-trimming of salmon fillets.

Design/methodology/approach

A prototype concept system was developed to explore the possibility of robotic post-trimming. The concept is based on 3D machine vision, a high-speed robot manipulator and a flexible light-weight cutting knife.

Findings

The developed prototype demonstrated the feasibility of detecting a pre-defined object to be trimmed in 3D, and performing the specified trimming cut along a 3D cutting trajectory.

Research limitations/implications

The developed prototype system was built and integrated – focusing so far only on a single trimming operation: the tail cut.

Originality/value

The originality in the paper is the description of a prototype integrated system, focused on robotic post-trimming of salmon fillets. The value is in providing a starting point for further development toward a complete robotic post-trimming of salmon fillets.

Details

Industrial Robot: An International Journal, vol. 43 no. 4
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 1 March 1986

B. Lejeune

Large ohm film resistors that guard sensitive telecommunication devices against the hazards of lightning require a set of exacting characteristics for tolerance, endurance, and…

Abstract

Large ohm film resistors that guard sensitive telecommunication devices against the hazards of lightning require a set of exacting characteristics for tolerance, endurance, and productivity. These characteristics largely depend on how the resistor is trimmed. Conventional laser trimming is unable to provide all the requirements for this important resistor application. A new technique developed by Teradyne Inc. called Algorithmic Trimming employs an algorithm and data base to calculate real‐time trim vectors that are used in a trimming hardware processor to overcome the drawbacks of conventional trimming. With this new technique 50‐ohm film resistors were trimmed to specification with 0·1% tolerance while attaining high resistor stability and a trim time of 300 milliseconds.

Details

Microelectronics International, vol. 3 no. 3
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 2 October 2018

Humphrey Boogaerdt and Alistair Brown

The purpose of this paper is to consider the monetary valuation implications arising from local government tree trimming, by calculating the loss of local government authority’…

Abstract

Purpose

The purpose of this paper is to consider the monetary valuation implications arising from local government tree trimming, by calculating the loss of local government authority’ monetary tree value arising from trimming trees under power lines.

Design/methodology/approach

A city council model of estimation of the monetary value of city trees in a sample of three streets in a suburb of the Perth Metropolitan Area in Western Australia is applied to ascertain the loss of monetary value to the local government authority arising from tree trimming.

Findings

Using a sample of 274 city trees, the results of the study show that 156 city trees did not get trimmed thus incurring no monetary loss. However, the average loss of monetary value from 118 city trees that were trimmed was AU$2,816 per tree, suggesting a substantial loss of value to the council.

Research limitations/implications

The use of monetary tree valuation should be treated with caution as there is a focus on monetary calculations rather than non-monetary evaluations of trees. Further, the analysis does not take into account increases in value of city trees resulting from their growth.

Practical implications

In trimming trees, monetary value and canopy cover of trees may be reduced. In terms of property management, it may be helpful for the city council to take into account loss of city tree value from tree trimming when considering a cost-benefit analysis of the above ground/underground trade-off of power line installation.

Social implications

With increasing populations and demand on services, local government authorities may use monetary valuation techniques of trees to provide an accountability to ratepayers.

Originality/value

The results highlight the value loss of trimming a tree. The study’s originality rests in providing local government authority a valuation.

Details

Property Management, vol. 37 no. 2
Type: Research Article
ISSN: 0263-7472

Keywords

Article
Publication date: 1 January 1986

R. Ronniger

High speed chip resistor trimming requires a more advanced technology than just passive network‐trimming. Some guidelines have to be observed to obtain a good approach to the…

Abstract

High speed chip resistor trimming requires a more advanced technology than just passive network‐trimming. Some guidelines have to be observed to obtain a good approach to the desired goal. One fast and inexpensive way of finding the best parameters for a trim cut, i.e., maximum speed and best accuracy, is CAD‐network simulation. Last but not least several parameters should be checked and controlled continuously to optimise yield.

Details

Microelectronics International, vol. 3 no. 1
Type: Research Article
ISSN: 1356-5362

Book part
Publication date: 18 January 2022

Yoonseok Lee and Donggyu Sul

This chapter develops robust panel estimation in the form of trimmed mean group estimation for potentially heterogenous panel regression models. It trims outlying individuals of…

Abstract

This chapter develops robust panel estimation in the form of trimmed mean group estimation for potentially heterogenous panel regression models. It trims outlying individuals of which the sample variances of regressors are either extremely small or large. The limiting distribution of the trimmed estimator can be obtained in a similar way to the standard mean group (MG) estimator, provided the random coefficients are conditionally homoskedastic. The authors consider two trimming methods. The first one is based on the order statistic of the sample variance of each regressor. The second one is based on the Mahalanobis depth of the sample variances of regressors. The authors apply them to the MG estimation of the two-way fixed effects model with potentially heterogeneous slope parameters and to the common correlated effects regression, and the authors derive limiting distribution of each estimator. As an empirical illustration, the authors consider the effect of police on property crime rates using the US state-level panel data.

Details

Essays in Honor of M. Hashem Pesaran: Panel Modeling, Micro Applications, and Econometric Methodology
Type: Book
ISBN: 978-1-80262-065-8

Keywords

Article
Publication date: 1 February 1985

P. Thompson

With increased application of hybrids, methods have been developed enabling resistor films to be cut away until the resistor has precisely the required value for correct…

Abstract

With increased application of hybrids, methods have been developed enabling resistor films to be cut away until the resistor has precisely the required value for correct functioning. Passive trimming is giving way to active or functional trimming where the frequency response itself is adjusted using a sine wave generator and waveform analysis equipment. Some of the problems encountered in trimming are discussed, including those caused by the high energy laser light itself; the effect on active circuits caused by the generation of Ipp currents; and DC offset or level shifts produced by low level light. The importance of producing a system in which laser, instrumentation and computer are programmed in one language is emphasised. Finally the advantages of functional trimming are summarised.

Details

Microelectronics International, vol. 2 no. 2
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 1 March 2006

Richard Bloss

To relate how even a smaller manufacturing operation can benefit from the application of robotic methods to manual operations.

Abstract

Purpose

To relate how even a smaller manufacturing operation can benefit from the application of robotic methods to manual operations.

Design/methodology/approach

A maker of fibreglass automobile body kits called in a robotic systems integrator with 20 years of experience to automate his manual panel trimming operation. In about three months, the system integrator delivered a complete system to meet all application requirements.

Findings

The auto body kit maker achieved a 95 percent reduction in trimming time and improved his quality as well.

Research limitations/implications

While this manufacturer achieved dramatic benefits, not all trimming operations might achieve such results.

Practical implications

Key to a successful robot application can depend heavily on the skills and prior experience of the system integrator selected to address the application.

Originality/value

May provide incentive to other smaller fiberglass panel manufacturers to examine potential applications where robotic trimming systems could provide excellent pay back on the investment.

Details

Industrial Robot: An International Journal, vol. 33 no. 2
Type: Research Article
ISSN: 0143-991X

Keywords

Book part
Publication date: 19 December 2012

Jingjing Yang and Timothy J. Vogelsang

We analyze Lagrange Multiplier (LM) tests for a shift in trend of a univariate time series at an unknown date. We focus on the class of LM statistics based on nonparametric kernel…

Abstract

We analyze Lagrange Multiplier (LM) tests for a shift in trend of a univariate time series at an unknown date. We focus on the class of LM statistics based on nonparametric kernel estimates of the long run variance. Extending earlier work for models with nontrending data, we develop a fixed-b asymptotic theory for the statistics. The fixed-b theory suggests that, for a given statistic, kernel, and significance level, there usually exists a bandwidth such that the fixed-b asymptotic critical value is the same for both I(0) and I(1) errors. These “robust” bandwidths are calculated using simulation methods for a selection of well-known kernels. We find when the robust bandwidth is used, the supremum statistic configured with either the Bartlett or Daniell kernel gives LM tests with good power. When testing for a slope change, we obtain the surprising finding that less trimming of potential shift dates leads to higher power, which contrasts the usual relationship between trimming and power. Finite sample simulations indicate that the robust LM statistics have stable size with good power.

Article
Publication date: 5 May 2015

Busi Rambabu and Y. Srinivasa Rao

The purpose of this paper is to study high-voltage interactions in polymer thick-film resistors, namely, polyvinyl chloride (PVC)-graphite thick-film resistors, and their…

Abstract

Purpose

The purpose of this paper is to study high-voltage interactions in polymer thick-film resistors, namely, polyvinyl chloride (PVC)-graphite thick-film resistors, and their applications in universal trimming of these resistors.

Design/methodology/approach

The authors applied high voltages in the form of pulses and impulses of various pulse durations and with different amplitudes to polymer thick-film resistors and observed the variation of resistance of these resistors with high voltages.

Findings

The paper finds that high voltages can be used for trimming of polymer thick-film resistors in both directions, i.e. upwards and downwards.

Research limitations/implications

The research implication of this paper is that polymer thick-film resistors can be trimmed downwards or upwards practically using this method.

Practical implications

The practical implications of this paper is that one can trim the polymer thick-film resistors, namely, PVC–graphite thick-film resistors, in both directions, i.e. upwards and downwards, by using this method.

Originality/value

The value of the paper is in showing that high voltages can be used to trim downwards and also upwards in the case of polymer thick-film resistors. This type of trimming is called universal trimming, developed first time for polymer thick-film resistors.

Details

Microelectronics International, vol. 32 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

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